Not applicable.
1. Field of the Invention
The present invention relates to a downhole tool for oil and natural gas production. More specifically, the downhole tool enhances the ability of a well operator to hold pressure above a given depth by closure of a flapper assembly.
2. Description of the Related Art
In hydrocarbon wells, fracturing (or “fracing”) is a technique used by well operators to create and/or extend a fracture from the wellbore deeper into the surrounding formation, thus increasing the surface area for formation fluids to flow into the well. Fracing can be accomplished by either injecting fluids into the formation at high pressure (hydraulic fracturing) or injecting fluids laced with round granular material (proppant fracturing) into the formation.
Fracing multiple-stage production wells requires selective actuation of downhole tools, such as fracing valves, to control fluid flow from the tubing string to the formation. The specific actuator and actuated element for the downhole tool, however, can vary, and may include either mechanical shifting tools that operate on a profile of the tool, hydraulic shifting tools, etc.
One problem with tools used in fracing procedures and, more generally, oil and gas completion and production procedures, relates to the ability of the actuator and actuated element to withstand heightened pressures that may be achieved. The application of such heightened pressures, which may be generated by pumping equipment at the wellhead, creates a pressure differential across the actuator, applying force thereto. Generally, the actuation system (e.g., a ball-and-seat combination) is the weakest part of the tool, and therefore is most likely to fail under procedures. Despite this fact, actuation systems are commonly used as a fluid seal system for post-actuation procedures, such as fracing, which employ heightened pressures exceeding the plug's rating, i.e. the ability of the plug to maintain its seal against the plug seat. The actuator will fail when the force applied to it becomes sufficiently high—e.g. by breaking, by a plug extruding through the plug seat, by deformation, or other failures—even when all other parts of the tool remain pressure tight and the actuator's pressure rating thereby provides an upper pressure limit that can be exceeded during such procedures. By reducing the probability of the actuation system failing, overall reliability of the system is increased. This minimizes otherwise unexpected costs associated with having to remove all or part of the tubing string upon failure.
The system and method of the present disclosure addresses this problem by providing a stronger element, a flapper assembly, for withstanding such pressure differential and thereby removing the necessity that the actuation system withstand the heightened pressures as discussed above.
The embodiments of the present disclosure relate to a downhole tool that reduces the potential of an actuator or actuated element failing during a completion or production procedure. Certain embodiments of the apparatuses disclosed herein incorporate a sleeve assembly with an actuatable element, such as the seat of a ball-and-seat combination, and a flapper assembly. The sleeve assembly is movable, either longitudinally, radially, or both, between a first position, in which the flapper assembly is open and inhibited from closing by the positioning of the sleeve assembly in the first position, and a second position in which the flapper assembly is closed. Upon closing of the flapper assembly, the downhole tool may withstand higher pressures with reduced risk of failure of the actuator, which generally has the highest risk of failure, improving the reliability of the tool for environments or operations requiring higher pressure on one side of the actuator element than on the opposing side of the actuator element.
When used with reference to the figures, unless otherwise specified, the terms “upwell,” “above,” “top,” “upper,” “downwell,” “below,” “bottom,” “lower,” and like terms are used relative to the direction of normal production and/or flow of fluids and/or gas through the tool and wellbore. Thus, normal production results in migration through the wellbore and production string from the downwell to upwell direction without regard to whether the tubing string is disposed in a vertical wellbore, a horizontal wellbore, or some combination of both. Similarly, during the fracing process, fracing fluids and/or gasses move from the surface in the downwell direction to the portion of the tubing string within the formation.
As shown in
During production, hydrocarbons will generally migrate in a first direction 31 from the second end 24 to the first end 22 through a generally-cylindrical flow path 34 defined by a longitudinal axis 36 and which intersects the interior volume. During fracing, completion fluids will generally flow in a second direction 33 from the first end 22 to the second end 24.
Referring specifically to
Referring jointly to
Referring specifically to
As shown in
Referring jointly to
Referring to
The seat housing 116 includes first and second internally-threaded ends 132, 134 that are engaged with the second end 122 of the first sleeve 112 and the first end 126 of the second sleeve 114, respectively. The seat housing 116 further includes an intermediate section 136 between the first end 132 and the second end 134. The intermediate section 136 is defined by first and second annular shoulder surfaces 138, 140. The seat housing includes a cylindrical outer surface 144 extends between the first end 132 and second end 134.
A plurality of cylindrical recesses 142 are formed in, and circumferentially aligned around the cylindrical outer surface 144 of the seat housing 116. A plurality of circumferentially-aligned shear pins 146, each having a predetermined shear strength, extends through the holes 76 in the adaptor sub 32 into the recesses 142.
A cylindrical groove 148 is formed in the outer surface 144 of the seat housing 116. A lock ring 150 having dogs 152 occupies the groove 148. The lock ring 150 is a split ring, or C-ring, radially expandable between compressed and expanded states. As shown in
Still referring to
After termination of the fixed relationship, longitudinal movement of the sleeve assembly 110 is limited in the first direction 31 by contact of the first end 132 of the seat housing 116 with the flapper mount 94. Longitudinal movement of the sleeve assembly 110 is limited in the second direction 33 by contact of the second end 134 of the seat housing 116 with the first end 80 of the bottom sub 28.
Referring to
In this state, fluids may flow through the embodiment in the first direction 31, provided the flow pressure is sufficient to overcome the rotational force of the torsion springs 102, 104 (see
Movement of the sleeve assembly to the second position may not, in certain embodiments, directly allow the plate to move and seal against the flapper seat. For example, Applicant's U.S. patent application Ser No. 13/694,509 filed on Dec. 7, 2102 and entitled “Flow Bypass Device and Method” (the '509 Application) discloses a lock system which is released when a sleeve assembly is moved from a first position to a second position, releasing a second sleeve or other element to then move. It will be appreciated that the sleeve assembly and seal assembly of the present disclosure could be engaged with such a locking system, such that movement of the sleeve assembly releases the lock. An additional step, such as movement of a second sleeve, may then permit movement of the plate and formation of a seal between the plate and the flapper seat. Other methods for releasing the plate upon, including methods for releasing the plate in response to movement of the sleeve assembly, will become apparent upon study of the present disclosure and are within the scope of the invention as claimed.
The disclosure made herein describes one or more preferred embodiments of systems and methods within the scope of the claims. Those skilled in the art will recognize that alternative embodiments of such a systems and methods can be used in carrying out the claimed invention. Other aspects and advantages of the disclosed systems and methods may be obtained from a study of this disclosure and the drawings, along with the appended claims.
This nonprovisional application claims the benefit of and priority to U.S. provisional application Ser. No. 61/729,262, filed Nov. 21, 2012 and entitled “Downhole Tool Incorporating Flapper Assembly,” and is a continuation-in-part of U.S. patent application Ser. No. 14/034,072, which is a Continuation of U.S. application Ser. No. 12/909,446 filed Oct. 21, 2010, issued as U.S. Pat. No. 8,540,019, entitled “Fracturing System and Method”; each of which is incorporated by reference as if fully set forth herein.
Number | Date | Country | |
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61729262 | Nov 2012 | US |
Number | Date | Country | |
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Parent | 12909446 | Oct 2010 | US |
Child | 14034072 | US |
Number | Date | Country | |
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Parent | 14034072 | Sep 2013 | US |
Child | 14086879 | US |